Why am I unable to shutdown my Linode?

Non Responsive to ACPI requests:

This can happen for a few reasons. For instance, your Linode may not be configured to respect ACPI shutdowns. This is usually not recommended since ACPI requests are an important in regard power management and system functionality, but depending on your needs as an administrator this could be a factor.

ACPI is handled in your boot loader's configuration file, for example:

/etc/default/grub
/etc/grub2.cfg

Although disabling your Linode's ability to power off isn't inherently dangerous, unless disabling this feature solves a direct system need, it can lead to unforeseen issues (like being unable to Warm Migrate).

If you suspect this could be an issue you can review your system logs for ACPI related messages and by using the `sudo dmesg' command:

This will search for any output from your system referencing ACPI
sudo dmesg | grep "acpi" 

/var/log/syslog or /var/log/messages

Hung Processes:

When a shutdown occurs it attempts to send signals to running processes to move them towards a graceful termination by performing cleanup tasks or saving their state prior to termination. If a process becomes "hung" it is in an infinite loop which can prevent that graceful shutdown and subsequent power-down request.

For more information about how to kill a hung process, check out the guide below:

• Use killall and kill Commands to Stop Processes on Linux | Linode Docs

If you are unsure of how to discern whether a process is "hung" you can use the following for loop to check for a hung process:

for x in `seq 1 1 30`; do ps -eo state,pid,cmd | grep "^D"; echo "-"; sleep 2; done